The present invention is directed to a molten metal sampling device such as that disclosed in my U.S. Pat. No. 4,120,204. A typical sampling device includes a mold supported at one end of a tube for immersion into a bath of molten metal below any slag layer. As molten metal enters the mold, air from within the mold must escape. In order to produce a suitable sample, it is a requirement that the mold should be completely filled. Due to this requirement, it is difficult to avoid overflowing the mold by the metal passing out through the vent. Overflowing presents a problem in opening the mold and in time lost in preparing a sample.
One manner in which venting of air from the mold is shown in FIGS. 6 and 7 of said U.S. patent wherein a cylindrical extension of the chamber is necked down to an air discharge port. Control of air venting in that manner is difficult to attain since the vent must be of sufficient cross-section in order to readily permit discharge of air while preventing discharge of molten metal.